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SS amp mosfet 'haze' - ever experienced this?

Tried a new amp in my system on the weekend: the well-reviewed Gamut D200 mkIII (partly based on HP's great review), a single-mosfet SS design. At the dealers' place, it sounded great (speakers were Wilson Benesch Discovery, an isobarak, lower-efficiency design). I can't use a tube amp right now (unfortunately!) due to pending child and the system is on a LOT (2-ch/HT mix), so am looking for the most full-bodied SS amp I can find (prefer fully balanced design to match my modded SF Line 3 pre).

Well, to my surprise, the amp did NOT work out as well at my place. My speakers are 97db Coincident Total Victory. Yes, it was full-bodied, but I was definitely aware of this haze, or veiling around each note. I have a friend who designs amplifiers, and he said that this is inherent of mosfet designs. I called Israel (Coincident) and he was not surprised that I only heard this once I got back to my place, due to the high resolution abilities of my speaker vs the speakers at the dealer's. I guess I will be sticking with my Sim Audio W-3, as it is much 'cleaner' on my system (given that I must stay with SS). Too bad, 'cause my Sim W-3 definitely has the edge in clarity, but the Gamut was a touch more full-bodied.

Has anyone else experienced this 'haze' with a mosfet-based design? I admit, those with higher-efficiency speakers like mine (97db/14ohm) probably are NOT using higher-powered mosfet designs anyways, but I would like to know how others feel about mosfet designs and this issue I had.
sutts

Showing 6 responses by jtgofish

jtgofish's avatar
jtgofish
497 posts
 
Hazy is how the vast majority of SS amps sound.Compressed too.Efficient speakers just highlight it more.
The one exception seems to be chip amps that can sound amazingly clear and fresh on sensitive speakers.
jtgofish's avatar
jtgofish
497 posts
 
It is a generalisation and I accept that a lot of people don't seem to hear this and maybe never will.We do not all hear or at least listen the same way,but there are also many people who hear this haze and prefer valve amps.Not that some of them don't also sound hazy,but the good ones certainly don't.
You owe it to yourself to hear the chip amps.Use one for a while and then switch back to your transistor amp.You will probably get a real shock regarding midrange congestion [imaging,dynamics,clarity,speed] just as I did.Over the years I have owned and tried all sorts of SS amps[even single ended class A].I can't say that I did not enjoy listening to some of them but everything is relative,and these devices really are becoming dinosouars[good for driving bass though],and probably would have become so a long time ago but for the conservatism of amp designers.[or unwillingness to embrace alternatives]
jtgofish's avatar
jtgofish
497 posts
 
Muralman,
I am interested to hear about the way chip amps switch compared to transistors and why this could be a clue as to their sound.
Are there any web articles about this?
jtgofish's avatar
jtgofish
497 posts
 
Kalan,
If you want fleshed out treble you should hear a Supratek Grange or Cabernet preamp with TJ meshplate 300Bs.Nothing I have heard comes even close.This is what I have been using with my $300 chip amp.An absurd mix of budgets and technology I know but it really works.
jtgofish's avatar
jtgofish
497 posts
 
The chip amps I am refering to are the Gainclone type.They use Panasonic chips.I have two of these-a paralelled 4780 which is 100watts RMS and will drive difficult loads and a 3876T Sonic Art which is 56 watts RMS.They both sound very similar to me but the 3876T is probably a bit warmer and open in the midrange.

JT
jtgofish's avatar
jtgofish
497 posts
 
Kalan,
Yes my chip amps do sound best with efficient speakers but are also very good on hybrid stas that are quite a difficult load.
On balance I still prefer a good valve amp but these things ,to my ears, still leave the vast majority of transistor and digital types for dead.The fact that you can put a kit one together for around $300 makes them really special.If nothing else they are excellent back up amps to SETS or big PP valve amps and great for using when the temperature is just too hot to put up with hot running valves.
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